NaOH-etched/boron-doped nanohydroxyapatite-coated PEEK implants enhance the proliferation and differentiation of osteogenic cells

Abstract

The aim of the present study is to eliminate the bioinertness of polyetheretherketone (PEEK) material and to increase its osteogenic activity by applying a number of surface modifications in order to discover the most effective method. First, the surface of the bare PEEK (B-PEEK) was mechanically modified by sandblasting (S-PEEK). As a second method, physical modification was provided by etching of B-PEEK in 10 M sodium hydroxide (NaOH) solution at 60 °C for 48 h (N-PEEK). Following the sandblasting, S-PEEK samples were also etched with NaOH to obtain SN-PEEK samples. In order to increase osteogenic activity of the mechanically and/or physically modified PEEK samples, they were coated with boron-doped nanohydroxyapatite (B-nHAp) in the presence of microwave energy. Thus, B-PEEK/B-nHAp, S-PEEK/B-nHAp, N-PEEK/B-nHAp and SN-PEEK/B-nHAp samples were obtained. While water contact angles and surface roughness of the B-PEEK samples increased after modification, hydrophilicity increased with B-nHAp coating. Cell culture results demonstrated that high proliferation and differentiation capacities of MC3T3-E1 cells were obtained on the B-nHAP-coated surfaces compared to uncoated specimens. However, channeled texture of both the N-PEEK and N-PEEK/B-nHAp samples enhanced Col1a1 mRNA expression and collagen secretion in addition to increased alkaline phosphatase (ALP) activity when compared to other groups. As a result, it was determined that the bioactivity increased on the modified PEEK surfaces, but the most effective osteogenic activity was provided with B-nHAp coatings. The synergetic effect of NaOH etching and B-nHAp coatings might be used as a promising surface modification method to use PEEK material in orthopedic and dental applications with increased osteogenic activity.

In Vivo Evaluation of the Effects of B-Doped Strontium Apatite Nanoparticles Produced by Hydrothermal Method on Bone Repair

“…In these studies, it has been shown that boron has positive effects on bone healing [ 20 , 25 ]. Boron (B) modulates the osteogenic effects of human bone marrow-derived mesenchymal stem cells [ 70 , 71 ] and mineralized tissue-related proteins as well as the adhesion and proliferation potential of osteoblasts [ 72 ]. In various studies using these elements separately, it has been reported that strontium and boron ions have positive effects on bone formation [ 64 , 65 , 66 , 73 ].…”

Strategies to improve bioactive and antibacterial properties of polyetheretherketone (PEEK) for use as orthopedic implants

“…These surface modifications lead to the enhancement of PEEK bioactivity, allowing for easier integration with native bone tissue while maintaining PEEK's original mechanical properties. However, surface modification also has some disadvantages, such as poor adhesion due to changes in material crystallinity and high-temperature conditions [ 39 ]. The advantages and disadvantages of some surface modification techniques are summarized in Table 2 .…”

“…In addition, NaOH etching and B-nHA treatment increased ALP activity, COL1A1 mRNA expression, and collagen secretion. This suggests that B-nHA treatment, NaOH etching, or a combination of the two can enhance osteogenic activity [ 39 ]. Johansson et al.…”

“… Modification strategy Coatings or Fillers Research results related to the bioactive property Reference Hydroxyapatite coating B-nHA In vitro : increased cytocompatibility, differentiation, COL1A1 mRNA expression, and collagen secretion. [ 39 ] Nanoscale HA In vivo : torque values of the tibia and femur in rabbits were higher. [ 48 ] Nanoscale HA In vivo : improved the osteogenic ability of the rabbit femur.…”

A microporous surface containing Si3N4/Ta microparticles of PEKK exhibits both antibacterial and osteogenic activity for inducing cellular response and improving osseointegration

“…Therefore, osseointegration of PAEK is considered as the gold standard for successful implantation in vivo [ 8 ]. Several strategies (e.g., surface modification with physical, chemical and biological ways) have been applied to increase the surface bioactivity of PAEK (e.g., PEEK) to facilitate new bone regeneration and osteointegration, such as plasma treatment, NaOH-etched/boron-doped nanohydroxyapatite coating or a bone morphogenetic protein-2 immobilized collagen coating on PEEK [ [9] , [10] , [11] ]. However, these surface modification strategies may not be sufficient to produce biomedical implants with excellent osteogenic bioactivity and stability for clinical applications [ 12 , 13 ].…”